nmbug: Add --no-renames to default log options

nmbug: Add --no-renames to default log options

Git has supported this since b68ea12e (diff.c: respect diff.renames
config option, 2006-07-07, v1.4.2).  All of our information is in the
paths (the files are empty), so we don't want rename detection.  By
using --no-renames, we get entries like:

  $ nmbug log -- e473b453a2
  commit e473b453a25c072b5df67d834d822121373321f5
  Author: David Bremner <david@tethera.net>
  Date:   Sun Sep 25 07:54:11 2016 -0300

  D       tags/1474196252-31700-1-git-send-email-markwalters1009@gmail.com/0.23
  A       tags/1474196252-31700-1-git-send-email-markwalters1009@gmail.com/pushed

  ...

Instead of the old:

  $ nmbug log -- e473b453a2
  commit e473b453a25c072b5df67d834d822121373321f5
  Author: David Bremner <david@tethera.net>
  Date:   Sun Sep 25 07:54:11 2016 -0300

  R100    tags/1474196252-31700-1-git-send-email-markwalters1009@gmail.com/0.23   tags/1474196252-31700-1-git-send-email-markwalters1009@gmail.com/pushed